News Release Number: STScI-2006-04

Monster Black Holes Grow After Galactic Mergers

January 10, 2006: An analysis of the Hubble Space Telescope's deepest view of the universe
offers compelling evidence that monster black holes in the centers of
galaxies were not born big but grew over time through repeated galactic
mergers. The Hubble Ultra Deep Field (HUDF) studies also confirm recent
computer simulations that predict that newly merging galaxies are
enshrouded in so much dust that astronomers cannot see black holes
feasting on stars and gas from the mergers. The computer simulations,
as supported by Hubble, suggest that it takes hundreds of millions to a
billion years before enough dust clears so that astronomers can see the
black holes feasting on stars and gas from the merger. These
postage-stamp-size images reveal 36 young galaxies caught in the act of
merging with other galaxies. These galaxies appear as they existed many
billions of years ago. Astronomers have dubbed them "tadpole galaxies"
because of their distinct knot-and-tail shapes, which suggest that they
are engaging in galactic mergers.